If a colleague has locked themselves out of the system then you have two options.
Option 1: they wait 15 mins and then they will be unlocked. They will then be able to try and login again.
Option 2: You can unlock them manually.
To do this, follow these steps:
Step 1 - navigate to the Company page and then the Users tab - a locked user will have a small padlock on their user card.
Step 2 - click on that user
Step 3 - in the banner simply click "unlock them".
They will now immediately be able to try and login again. However it is probably worth advising them to reset their password by following the forgotten password link on the login page.